CALIFORNIA

Obesity Drug Yields Results, Safe in Trials, Amgen Says

Pharmaceuticals: But some analysts are disappointed that the data do not show more effectiveness.

Amgen Inc. said Monday that preliminary data on a new obesity drug demonstrated that the drug is safe and appears to produce some weight loss.

Although the data are encouraging enough for Amgen to announce it will proceed with further trials of the drug, leptin, some industry observers are disappointed that there is not a clearer showing of effectiveness.

Although the purpose of the preliminary, or Phase I, trials was only to confirm the compound was safe, expectations for the drug have run high since 1995, when Amgen paid an unprecedented $20 million for rights to the gene that produces leptin.

Many investors and dieters have pinned their hopes on leptin being a breakthrough weight-loss treatment.

The data released Monday are less conclusive. Although obese patients taking leptin in the trial lost weight, those receiving the placebo also lost weight, a result that, Amgen said, was probably due to the nutrition and exercise counseling all trial participants received.

Although those patients receiving leptin lost more weight, Amgen said the difference was not always significant.

Among 30 obese people in the trial, for instance, those taking leptin lost an average of 4 to 9 pounds after 90 days, whereas those on the placebo lost an average of about 3 pounds.

"I thought it was relatively positive data," said Alex To, an analyst with Donaldson Lufkin & Jenrette. "The main purpose of Phase I trials is to demonstrate the feasibility of further development, and these trials achieved that."

But To said the feeling is generally negative among industry analysts who spoke with Amgen executives in a conference call after the data came out.